and former presidents carter, bush and clinton along with other world leaders will be in south africa tomorrow for a memorial service for nelson mandela. that bins at 4 a.m. eastern time. earlier today british prime minister david cameron and members of the british house of commons paid tribute to nelson mandela. here's some of the prime minister's statement. >> mandela was the embodiment of that struggle. he did not see himself as a helpless victim of history, he wrote it. we must never forget the evil of apartheid and its effect on everyday life. separate benches, separate buses, separate schools, even separate pews in church. interracial relationships criminalized, past laws and banning orders, a whole language of segregation that expressed man's inhumanity to man. nelson mandela's struggle was made ever more vital by acts of extreme brewalty on the part of the -- brutality on the part of the south african authorities. his was a journey that spanned six decades through nearly three decades of incarceration through to his negotiations that led to the end of apartheid and his electio